The present invention relates to a plastic conduit coupler with fire block capacity.
It is well known that conduit such as wire conduits, pipe lines etc. provide easy passage for fire from one area of a building to the next. Accordingly, it is extremely important that these conduits include fire blocks.
A typical fire block is one which blocks passage through a pipe line when the pipe line is subjected to excessive heat. Often fire blocks are made from intumescent material, which as is known in the art, expands when subjected to heat, to block fire through a pipe.
An example of a fire block provided in a pipe line is described in U.S. Pat. No. 3,156,263 issued Nov. 10, 1964 to Adelman. According to the Adelman patent, a steel pipe is provided with foam liner which expands or intumesces inwardly when the heat within the pipe reaches an excessively high level.
Another example of a fire block is described in U.S. Pat. No. 4,424,867 issued Jan. 10, 1984 to Mallow. According to the Mallow patent a sleeve of intumescent material is fitted around a pipe or cable where the pipe passes through a partition. In the event of excessive heat, the sleeve intumesces inwardly under the guidance of the sleeve to block the pipe. The intumescent sleeve is surrounded by intumescent wall filler which is totally separate from the sleeve. This wall filler hardens to prevent fire and smoke from moving through the partition around the pipe.
The installation of the Mallow system, including the fitting of the sleeve over the pipe and the filling of the wall with intumescent material around the sleeve is quite labour intensive. Furthermore, the Mallow system necessitates the creation of an otherwise unnecessarily large hole through the partition around the pipe to accommodate the overall system.
U.S. Pat. No. 4,143,671 issued Mar. 13, 1970 to Olson shows a pipe coupler which simply collapses inwardly to provide a pipe block in the event of excessive heat passing along the pipe.
There is no control in the Olson coupler as to the depth penetration of the pipes into the coupler and therefore, there cannot be any exact fitting of the coupler. Furthermore, the Olson coupler does not intumesce and cannot be used as a partition block and may not even be effective as a pipe block if there is excessive collapsing of the block.
U.S. Pat. No. 4,267,853 issued May 19, 1981 to Yamaguchi discloses a metal pipe coupler including a heat expandable rubber inner tube which expands internally of the coupler in the event of excessive heat. There is no external expansion and therefore the Yamaguchi coupler has no benefit as a wall block.
The present invention provides a conduit coupler which penetrates a fire rated separation in a building e.g., a wall, a floor etc. to couple plastic conduit on either side of the separation. The coupler of the present invention has plastic end regions for an overlapped accurately positioned sealed coupling with the plastic conduit with those end regions being separated by an intermediate region formed by a wall of plastic based intumescent material. This wall of the plastic based intumescent material defines a fluid flow passage through the coupler and has a sufficient thickness of the intumescent material to produce a complete blockage of the passage when the coupler is subjected to conditions which cause an intumescing of the wall forming material of the intermediate region of the coupler.